Disclosed herein is a tube switch actuator. More particularly, disclosed herein is a tube switch actuator comprising an incompressible fluid, wherein the tube switch actuator signals to a switch by non-electrical means.
A variety of switch actuators exist wherein the actuators are used on a variety of control applications, for instance, they are installed on doors, machinery, equipment and under rugs to control the doors, machinery, equipment or operate burglar alarms, etc. Such actuators include, for example, mat and tape electric contact switches and air diaphragm type switches.
Conventional tape switch actuators generally comprise a pair of tapes or ribbons which are separated by one or more insulating strips so that they are not in contact. The assembly is covered by a plastic cover. When the tape switch is pressed at any point along its length by a hand, foot, vehicle wheel, etc., the contact will be made for controlling another circuit, for instance, for opening doors, operating burglar alarms and lights, operating counters, etc. Such conventional tape switches are described, for example, in U.S. Pat. Nos. 2,938,977; 3,052,772 and 3,710,054.
Conventional map switches generally incorporate switches into floor mats in the vicinity of machinery to open or close electrical circuits. For example, a floor mat switch which closes an electrical circuit when stepped on may be used as a safety device to shut down machinery when a person walks into an unsafe area in the vicinity of the machinery. Conversely, the floor mat switch can be used to close a circuit and thereby keep machinery operating only when the person is standing in a safe area. Alternatively, the floor mat switch may be used to sound an alarm when stepped on, or to perform some like function. Mat switches typically include an electrical contact disposed between two mat substrates. The electrical contact is operable under pressure between a closed condition and an open condition and is maintained in either the opened or closed condition in the absence of pressure. One of the substrates of the mat transmits activating compression to the electrical contact. The electrical contact is typically a ribbon switch that may either run continuously or intermittently along the perimeter of the substrates. The ribbon switch is composed of electrical conductors which electrically engage upon compressing the substrate to activate the switch.
Also known in the art are compressible piezoresistive materials which have electrical resistance which varies in accordance with the degree of compression of the material. Such piezoresistive materials are disclosed in U.S. Pat. Nos. 5,060,527, 4,951,985, and 4,172,216, for example.
Electric flat tapeswitches, typically utilized in mat switch constructions, have problems in flexibility. That is, these tapeswitches can only bend in an upward and downward fashion, and therefore, cannot be easily contoured to fit the shape of their respective attachment sites. Therefore, construction of mats and strip applications are complex and expensive as they require corner connectors, and to operate most industrial equipment, such as gate and door openers, the electric tapeswitch requires additional expensive step up relays. Additionally, these tapeswitches require a considerable amount of force needed to activate the corresponding signals.
Although air diaphragm type switches have removed the necessity for electrical tape switches, these switches require a large volume of compressible air to actuate a switch by a movement of a large diaphragm. This system has proven cumbersome and is not adequate for sensitive applications.
Therefore, what is required is an actuator having improved flexibility, reduced motion loss, increased sensitivity, and lower costs of manufacture. Further needed is an actuator that can signal a switch by non-electrical means, thereby removing those dangers inherent in electrical activity.
The above problems are alleviated by an actuator comprising a flexible tubing comprising an amount of incompressible fluid contained in the inner portion of the flexible tubing; and a switch disposed on the top surface of an outer portion of the flexible tubing; wherein the actuator functions by moving the incompressible fluid through the tube such that a second force is directed onto the switch in response to a first force applied to the flexible tubing. Further disclosed herein is a method for forming the actuator described above.